Method of flexible connection

ABSTRACT

A flexible connector may include a tube having an open end and a lower end distal from the open end, an inner surface of the open end comprising a plurality of apices forming a substantially polygonal lower cross-section, an upper shaft having an insert end disposed insertably in the open end, an outer surface of the insert end comprising a plurality of substantially planer flats forming a substantially polygonal upper cross-section normal to the driven axis of rotation, the upper cross-section being substantially similar to the lower cross-section, and an elastic member disposed compressably between each of the flats and each of the apices.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a divisional of U.S. Ser. No. 11/043,067, filed Jan.27, 2005, now U.S. Pat. No. 7,329,189, issued Feb. 12, 2008, the entirecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the field of connectors, and more particularlyto connectors of the flexible variety.

2. Description of the Related Art

Segments of rotating shafts, such as auger shafts, may have to bend.Shafts may be made to bend by fitting them with joints. These joints arerequired to transfer torque between segments of rotating shafts as wellas allowing some axial misalignment of one segment relative to another.Auger sections used with tractors may experience high impact loads whenstarting. Tractors with high (200+ hp) power motors may produceparticularly large impact loads. A tractor that applies a high inputpower to move a large auger inertia may impart a severe strain on anauger coupling.

Some examples of joints that may be used to connect segments of rotatingshafts are universal or constant velocity joints. Splined sections mayalso be installed between segments of rotating shafts to take up axialdisplacement of one segment relative to another segment. Sometimesuniversal or constant velocity joints are combined with splinedsegments, like a propellor shaft on an automobile. Separate splinedsection to adjust for length takes up space, and it's difficult to wrapa helical blade around a spline.

A four-prong drive dog may be used to reduce impact by reducing theamount of rotation between the two auger sections before contact. Afour-prong drive dog, however, may not allow the spiral planes, i.e.edges of the connecting auger blades to align. Elastic or “rope” driveshave been tried as well. Rope drives, however, wind up, storing someenergy in the form of deformation before releasing it. Such storage andrelease impart differences in angular velocities between the shaftsegments they connect. These angular velocity differences causevariations in the speeds at which materials proceed through the auger.Speed differences produce local pile-ups of material that may contributefurther to clogs and clumps, which may interfere with the auguringprocess.

Furthermore, a rope or elastic member stretched between two segments ofa shaft to impart rotational motion will necessarily be loaded intension and shear. Elastomers, such as rubber, is often quite weak intension or shear. An elastic connector may thus load the elastic memberwhere it's weakest, in tension.

Augers may transport granular materials, such as grain, dust or silage.Granular or dusty materials may interfere with the operation of auniversal or a constant velocity joint. The joint may become gummed up,and the moving parts of the joint may experience significant wear due tothe materials being transported. Furthermore, the sliding surfaces ofconstant-velocity joints may become contaminated with silt and debris,making the joint work harder. Finally, universal joints, although cheapand robust, impart differences in angular velocities between the shaftsegments they connect. These angular velocity differences causevariations in the speeds at which materials proceed through the auger.Speed differences produce local pile-ups of material that may contributefurther to clogs and clumps, which may interfere with the auguringprocess.

SUMMARY OF THE INVENTION

A primary object of the invention is to overcome the deficiencies of therelated art described above by providing a flexible connector. Thepresent invention achieves these objects and others by providing aflexible connector.

In several aspects, the invention may provide a flexible connector. Inparticular, in a first aspect, a flexible connector may include a driveshaft having a drive end, a drive lug disposed fixedly at a surface ofthe drive end, a lower shaft disposed insertably within the drive end,the lower shaft having a driven lug disposed fixedly at a surface of thelower shaft substantially abutably to the drive lug, a tube having anopen end and a lower end distal from the open end, the lower enddisposed fixedly at the lower shaft, an inner surface of the open endcomprising a plurality of apices forming a substantially polygonal lowercross-section, an upper shaft having an insert end disposed insertablyin the open end, and an upper end distal from the insert end, an outersurface of the insert end comprising a plurality of substantially planerflats forming a substantially polygonal upper cross-section, the uppercross-section being substantially similar to the lower cross-section, anelastic member disposed compressably between each of the flats and eachof the apices, a driven shaft having a driven end, an insert aperturehaving a substantially polygonal insert cross-section disposed fixablyin the driven end, the insert cross-section being substantiallycongruent to the upper cross-section, the insert end disposed insertablywithin the insert aperture, wherein a torque applied to the drive shaftforces the drive lug against the driven lug, transmitting the torque tothe lower shaft and the tube, wherein the torque applied to the tubecompresses the elastic members against the flats, transmitting thetorque to the insert end and the upper end, and wherein the insert endtransmits the torque to the insert aperture and the driven shaft.

In a second aspect, a method of flexible connection may include thesteps of applying a torque to a drive shaft, forcing a drive lug againsta driven lug with the drive shaft, transmitting the torque to a lowershaft and a tube with the driven lug, compressing elastic membersagainst flats with the tube, transmitting the torque to an insert endand an upper end with the elastic members, and transmitting the torqueto an insert aperture and a driven shaft with the insert end.

In a third aspect, a system for flexible connection may include meansfor applying a torque to a drive shaft, means for forcing a drive lugagainst a driven lug, means for transmitting the torque to a lower shaftand a tube, means for compressing elastic members against flats, meansfor transmitting the torque to an insert end and an upper end, and meansfor transmitting the torque to an insert aperture and a driven shaft.

The above and other features and advantages of the present invention, aswell as the structure and operation of various embodiments of thepresent invention, are described in detail below with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and form partof the specification, illustrate various embodiments of the presentinvention and, together with the description, further serve to explainthe principles of the invention and to enable a person skilled in thepertinent art to make and use the invention. In the drawings, likereference numbers indicate identical or functionally similar elements. Amore complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a side view of a flexible connector according to a firstembodiment of the invention;

FIG. 2 is a three-quarter view of a flexible connector according to theembodiment shown in FIG. 1;

FIG. 3 is a three-quarter view of a flexible connector according to theembodiment shown in FIG. 1;

FIG. 4 is a side view of an augur for use with a flexible connectoraccording to the embodiment shown in FIG. 1;

FIG. 5 is a detail of the flexible connector of the auger shown in FIG.4;

FIG. 6 is an exploded view of an augur for use with a flexible connectoraccording to the embodiment shown in FIG. 1;

FIGS. 7A-7G are shapes of inner surface cross-sections for use with aflexible connector according to the embodiment shown in FIG. 1; and

FIGS. 8A-8G are shapes of outer surface cross-sections for use with aflexible connector according to the embodiment shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It would be desirable for a connector to transmit rotation from onesegment of an auger to the next with relatively constant velocity. Itwould further be desirable for a connector to tolerate some shaftmisalignment. It would further be desirable for a connector to toleratesome linear or axial translation of one segment of an auger relative tothe next. It would further be desirable for a helical augur blade to becontinuous over a connector.

It would be desirable for a connector to allow sections of auger to becombined to form augers of various lengths. It would be desirable for aconnector to be replaceable relatively easily. It would be desirable fora connector to be relatively tolerant of dimensional variations andinstability. It would be desirable for a connector to function even whenburied in grain or grain dust. It would be desirable for a connector tohave no moving parts, so won't matter if it's buried in silt. It wouldbe desirable for a connector to be inherently constant-velocity. Itwould be desirable for elastic elements in a connector to be loaded incompression, rather than in tension or shear.

In FIG. 1 through 3 is shown a flexible connector 100 according to afirst embodiment of the invention. In one embodiment, flexible connector100 may include a tube 114 having an open end 116 and a lower end 118distal from open end 116, and a drive axis of rotation 104. An innersurface 120 of open end 116 may have a plurality of apices 122 forming asubstantially polygonal lower cross-section 124 normal to drive axis ofrotation 104. In several embodiments, shown in FIGS. 7A-7G, lowercross-section 124 may be a square, a triangle, a quadrilateral, apentagon, a hexagon, a rhombus, or a trapezoid. In one embodiment, shownin FIG. 7C, lower cross-section 124 may be substantially square.

In one embodiment, a lower shaft 110 may be disposed fixedly at lowerend 118 substantially parallel to drive axis of rotation 104. In thisembodiment, lower shaft 110 may have a driven lug 112 disposed fixedlyat a surface of lower shaft 110. In one embodiment, driven lug 112 maybe offset a predetermined distance 178 from drive axis of rotation 104.

In one embodiment, an upper shaft 126 may have an insert end 128disposed insertably in open end 116, an upper end 130 distal from insertend 128, and a driven axis of rotation 132. Upper end 130 may have adrive aperture 134 substantially normal to driven axis of rotation 132.

An outer surface 136 of insert end 128 may have a plurality ofsubstantially planer flats 138 forming a substantially polygonal uppercross-section 148 normal to driven axis of rotation 132. In severalembodiments, shown in FIGS. 8A-8G, upper cross-section 148 may be asquare, a triangle, a quadrilateral, a pentagon, a hexagon, a rhombus,or a trapezoid. In one embodiment, shown in FIG. 8C, upper cross-section148 may be substantially similar to lower cross-section 124.

In one embodiment, an elastic member 156 may be disposed compressablybetween each of flats 138 and each of apices 122. In another embodiment,an elastic member 156 may be disposed compressably between at least oneof flats 138 and apices 122. In this embodiment, elastic members 156 maybe dispersed rotationally symmetrically about driven axis of rotation132, such as, for example, between every other flat 138/apex 122 pair,or between every third flat 138/apex 122 pair. In several embodiments,elastic member 156 may be a resilient cord, a polymeric cylinder, anelastomeric cylinder, or a length of braided metal or fibrous cable.

In one embodiment, shown in FIGS. 4 through 6, flexible connector 100may connect a drive end 106 of a drive shaft 102 to a driven end 142 ofa driven shaft 140 to form an auger 180. In one embodiment, a driveblade 158 may be disposed substantially helically about drive shaft 102.In this embodiment, a drive housing 160 may be disposed substantiallyconcentrically about drive blade 158. In this embodiment, drive housing160 and drive blade 158 may comprise a drive auger 164.

In one embodiment, a hanger 166 may be disposed in drive housing 160,and a bearing 168 may be disposed insertably at an end of hanger 166. Inthis embodiment, drive end 106 is may be disposed rotatably in bearing168. In one embodiment, lower shaft 110 may be disposed insertablywithin drive end 106.

In one embodiment, a driven blade 162 may be disposed substantiallyhelically about driven shaft 140. In this embodiment, a driven housing170 may be disposed substantially concentrically about driven blade 162.In this embodiment, driven housing 170 and driven blade 162 may comprisea driven auger 172. In one embodiment, drive blade 158 may line upsubstantially with driven blade 162 at flexible coupling 100.

In one embodiment, an insert aperture 144 having a substantiallypolygonal insert cross-section 146 may be disposed fixably in driven end142. Insert cross-section 146 may be substantially congruent to uppercross-section 148. Insert end 128 may be disposed insertably withininsert aperture 144. In one embodiment, insert end 128 may be pressedinto insert aperture 144. In an alternative embodiment, insert end 128may be slipped into insert aperture 144.

In one embodiment, driven shaft 140 may have a driven aperture 150proximate to drive aperture 134, and a bolt 152 may be disposedinsertably within drive aperture 134 and driven aperture 150.

In one embodiment, a drive lug 108 may be disposed fixedly at a surfaceof drive end 106. In this embodiment, drive lug 108 may be offsetsubstantially predetermined distance 178 from drive axis of rotation104. In one embodiment, driven lug 112 may substantially abut drive lug108.

In this embodiment, a torque 154 applied to drive shaft 102 may forcedrive lug 108 against driven lug 112, transmitting torque 154 to lowershaft 110 and tube 114. In this embodiment, torque 154 applied to tube114 compresses elastic members 156 against flats 138, transmittingtorque 154 to insert end 128 and upper end 130. In this embodiment,insert end 128 may transmit torque 154 to insert aperture 144 and drivenshaft 140. In an alternative embodiment, a torque 176 applied in theopposite direction may force drive lug 108 away from driven lug 112. Inthis embodiment, torque 176 may not be transmitted to lower shaft 110and tube 114. Thus, drive lug 108 and driven lug 112 may comprise aone-way drive coupling.

In one embodiment, flexible connector 100 may include an actuator 174operably connected to drive shaft 102, actuator 174 applying torque 154to drive shaft 102. In several embodiments, actuator 174 may be ahydraulic actuator, such as an hydraulic motor or a hydrostatic drivedriven by an hydraulic pump slaved to a tractor power take off (PTO)shaft, or plumbed into an hydraulic circuit of the tractor itself, achain or belt driven actuator slaved to a PTO, an electric motor, or apneumatic motor.

In a second embodiment, a method of flexible connection may include thesteps of applying torque 154 to drive shaft 102, forcing drive lug 108against driven lug 112 with drive shaft 102, transmitting torque 154 tolower shaft 110 and tube 114 with driven lug 112, compressing elasticmembers 156 against flats 138 with tube 114, transmitting torque 154 toan insert end 128 and an upper end 130 with elastic members 156, andtransmitting torque 154 to an insert aperture 144 and driven shaft 140with insert end 128.

The foregoing has described the principles, embodiments, and modes ofoperation of the present invention. However, the invention should not beconstrued as being limited to the particular embodiments describedabove, as they should be regarded as being illustrative and notrestrictive. It should be appreciated that variations may be made inthose embodiments by those skilled in the art without departing from thescope of the present invention.

While the invention has been described in detail above, the invention isnot intended to be limited to the specific embodiments as described. Itis evident that those skilled in the art may now make numerous uses andmodifications of and departures from the specific embodiments describedherein without departing from the inventive concepts.

While various embodiments of the present invention have been describedabove, they should be understood to have been presented by way ofexamples only, and not limitation. Thus, the breadth and scope of thepresent invention should not be limited by the above describedembodiments.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that the invention may be practiced otherwise than asspecifically described herein.

1. A method of flexible connection comprising: applying a torque to adrive shaft; forcing a drive lug against a driven lug with said driveshaft; transmitting said torque to a lower shaft and a tube with saiddriven lug; compressing elastic members against flats with said tube;transmitting said torque to an insert end and an upper end with saidelastic members; and transmitting said torque to an insert aperture anda driven shaft with said insert end.